We tried peanut butter, and they were interested, but not thirsty. Then we didn't fill their water trough in the evening, rather we depressed the level on the founts allowing water to drip for the now thristy pigs. Within a couple of minutes they were old hands at watering themselves.

The peanut butter does get their interest though, and then some.

Between the little metal self-feeder, and now the self-waterers, my job just got a bunch easier.